When it comes to viability rankings, not many people bother to rank every fully evolved pokemon. After all, who cares whether Beedrill is better than Hitmonchan, they're both abysmal and not worthy of use, so who really cares? However of the few people who do go to that effort, something I've noticed is that it's surprisingly common (among the few who bother) to list a single pokemon as being worse than Ditto. I think it's fair to say that this is hyperbole, and exaggerated way of highlighting how incredibly bad the pokemon in question really is. After all Ditto is, by design, the benchmark for being the worst pokemon in the game, so to rank something lower is to truly disparage whatever is ranked below it.
Every time this comes up, the reasoning is that, you can contrive a scenario where Ditto does something, where it theoretically is able to Transform into something useful, whereas the other pokemon has literally no useful applications. If you seriously examine it, that's a very bold theory, but as far as I know it's just that- a theory. I doubt that any of the players making this conjecture have seriously tried to use Ditto. I've done this in the past, but I'd never actually used Ditto until recently. Well, I'm not about to let an obviously terrible idea stop me from investigating. I have now tested Ditto, and got to 1500 on ladder, which for RBY I consider the minimum acceptable standard when laddering. And I can confidently conclude that I, and everyone else that ever suggested any fully evolved pokemon as being worse than Ditto, were/are tripping balls.
Now you might say "that's a rather bold and potentially inflammatory position for someone to take 2 paragraphs after they just described such rankings as hyperbole rather than sincere rankings". That's a reasonable criticism but I don't care because even as hyperbole, suggesting anything is worse than Ditto is profoundly stupid, and I can now say that from experience.
Let's run through all of the issues that Ditto has. First, its stats are awful and it has no resistances. Virtually everything can 2HKO it and its crit rate is poor. Its pre-Transform speed is bad, but it does outpace a few notable threats at least. Its extreme frailty means it's virtually impossible to bring in safely, but this pales in comparison to its greatest flaw.
Once Ditto is somehow brought into play, its only options are to immediately double out to a pokemon that can actually accomplish something, or spend a turn using Transform. This means that as soon as it enters play, everyone knows your opponent has a free turn to do whatever the hell they want. Both players know it, everyone watching knows it, people in the lobby who aren't even spectating know it, my Mum whose only experience of Pokemon was me watching the anime when I was 5 years old probably knows it as well. This means that the opponent can heal up, use status, switch, or simply murder this useless blob, all with zero immediate retaliation.
Ah, but then Ditto Transforms into something useful right? Well, uh, no. That doesn't work in practice, outside of extremely specific conditions, and in those circumstances it's even rarer still for Ditto to perform even marginally better than literally anything else. Its peak really is a handful of % points better than whatever other options were available to you, but even achieving that is a vanishingly rare feat. So I've talked a lot of shit about Ditto's potential to Transform into something useful, but what factors need to be considered?
The first factor is whether it can Transform without dying, which is pretty obvious. You're not really going to be Transforming into Rhydon anytime soon. The flipside that is perhaps easier to overlook, is whether Ditto can even achieve anything after Transforming. A number of pokemon such as Jynx, Chansey and Slowbro struggle to break through themselves while also generally being able to heal up, and in such scenarios the fact that Ditto only gets 5 PP per move means it will invariably lose the ensuing stall war. Switching these Pokemon into Ditto will completely negate. If these switches were predictable, you could perhaps exploit that, but because Ditto dies so easily they're not really guaranteed- murder is always a valid option.
So to use Ditto, you need to bring it in and Transform safely, and you need to ensure your opponent doesn't have any pokemon that aren't threatened by themselves. That's an extremely difficult scenario to set up, but the worst thing is even if you achieve this, Ditto is still probably worse than whatever it Transformed into. It only has 5 PP per move, and retains both its poor crit rate and its abysmal HP. In order for it to achieve anything close to an advantage, it needs more support. A LOT more support.
Chip damage is important for Ditto, since there's a realistic probability that it will be losing half its HP (if not more) to an attack as it sets up, putting it at a deficit. But what it really needs is status, and your options are far more limited than you might suspect. Frozen opponents would be nice, but the only time anyone's leaving a frozen Pokemon in on Ditto is if said Pokemon is the least threatening option available, or if they literally have no other choice (in which case the game is already decided). Sleep is also poor, because Ditto takes way too many turns to get going, meaning a wake is more than likely. That really leaves only paralysis as a viable support option.
So how does Ditto work in practice? Well, I initially sought to go through all the setup required for Ditto to really achieve anything, with visions of it countersweeping. Obviously, that really didn't work out- the conditions necessary are way too specific, and also so stringent that you've practically already won the match and don't need Ditto anyway. After all, you basically require the opponent to have no response to your Ditto other than a paralysed and weakened Pokemon.
Where I ended up finding value in Ditto was as a response to potential sleep or boom, situations where I'm at risk of having one of my pokemon incapacitated. If that sounds like Ditto is so worthless that's it's practically dedicated cannon fodder, well it is. But one trick Ditto does have going for it is if for whatever reason it survives entering play AND the opponent doesn't switch out, it can then turn whatever high impact move I was worried about back against the opponent. This can also apply if the opponent may choose Rest as well.
The best example I can give is paralysed Exeggutor. If I'm concerned about sleep or boom, I can switch in Ditto, and if it doesn't die or get slept, I then Transform and turn the tables. This is of course, negated by simply switching out, but usually that will mean my opponent brings in a non-threat, meaning I've temporarily neutralised the real threat. Another example is if you somehow whittle Lax down to about 40% and it's only clicked Body Slam. It will probably either Boom or Rest. If it's the former, you dodge a bullet by sacrificing a trash mon, while if they Rest, you can threaten to Transform into Lax, which opponents are seldom willing to allow you to do (even though you're still probably not beating Lax even with a free turn).
There are other marginal uses, but they amount to little- scouting sets, and transforming into an opposing status spreader if you're absolutely desperate are what I have in mind. Overall though, the majority of battles that I won, Ditto accomplished nothing, and the games I lost due to having wasted a teamslot would've easily outnumbered the games where Ditto's contributions weren't zero. Not once did it come close to providing the value necessary to justify a teamslot, it was challenging enough getting any value whatsoever out of it
In conclusion, Ditto is ass, worst pokemon in the game.
Replays:
https://replay.pokemonshowdown.com/gen1ou-1549602795-2jn1eyf88ieykem6g4jjl197rav41dhpw. This was easily the best Ditto match in that it wasn't totally useless and I was able to beat a solid player without obscene hax or them bringing dumb gimmicks (just a really fucking good matchup lol)
https://replay.pokemonshowdown.com/gen1ou-1512828090-10ikldnxfr04srzbwyukoty4dnc5tl4pw. Strongest performance from Ditto imo, but only because my opponent's last pokemon was Parasect lol. Slash Parasect is also one of Ditto's better matchups tbh- Ditto's HP isn't too much worse, while Ditto's better crit rate makes a difference when using Slash
https://replay.pokemonshowdown.com/gen1ou-1519154048-ps52u0z5wff8qhoj54bdtuf90t9j5ospw. Managed to get a bs countersweep with Ditto, but I don't consider this to actually be a good showing because it depended on my opponent blundering multiple times
https://replay.pokemonshowdown.com/gen1ou-1533302171-3o6m0jc8r1atl2mznwgojd27w61rr8spw. Closed out the game with Ditto, but it was practically won already
Also fun fact, if you look at the
showdown stats for March, 1760 weighted usage has Ditto at 18th, above pokemon like Dragonite, Golem and Articuno, while Ditto ranks 7th as a Jolteon teammate. I'm not remotely sorry for this.
Edit: to clarify, I don't mean to throw shade at people who have characterised anything as worse than Ditto, even though that's effectively what I did. I kinda adopted that tone because I thought it embellished the post, not out of ill intent (also I fall into that camp as well, so idk)
Also this was a torturous grind and I'm glad to finally be done with it
(unordered)
